TORONTO — A man who gunned down two people in Toronto’s landmark Eaton Centre mall is asking for a new trial, arguing the jury that convicted him more than two years ago was improperly selected.

Christopher Husbands was found guilty of two counts of second-degree murder in the deaths of Nixon Nirmalendran, 22, and Ahmed Hassan, 24.

He was also found guilty of five counts of aggravated assault and one count of criminal negligence causing bodily harm in the June 2012 shooting that sent hordes of panicked shoppers running for the exits.

Husbands, whose lawyers had put forward a defence of not criminally responsible due to post-traumatic stress disorder, was sentenced to life in prison with no chance of parole for 30 years.

His lawyer has said the sentence is unprecedented for second-degree murder.

The appeal, which is being heard Friday in Toronto, focuses largely on the manner in which jurors were chosen and refers heavily to an appeal court ruling in a case by the same trial judge.

As part of the selection process, prospective jurors may be questioned as to whether they believe they can remain impartial. Two people from the jury pool take on the role of “triers,” meaning they weigh the answer and determine whether there is sign of bias.

Lawyers for both the Crown and the defence then decide whether to allow the person on the jury.

Each newly appointed juror replaces one of the two triers so that the responsibility is shared, a process called “rotating triers.”

At the request of the accused, the court can appoint two people who will assess all the prospective juror responses. These are called “static triers” and do not get to serve on the jury.

As a result, they argue, Husbands was “tried and convicted by an improperly constituted court.”

Crown lawyers, meanwhile, say the judge wasn’t mistaken in choosing static triers. In any case, they say, “any error here occasioned the appellant no prejudice or miscarriage of justice.”

Two years ago, the court of appeal called for a new trial over the imposition of static triers in another case over which Ewaschuk presided.

In that ruling, the court noted the use of rotating triers has been a feature of the Canadian jury-selection process since the 1900s and that a properly constituted jury is critical to the entire process.